HedgeDoc is the community-driven fork of CodiMD, which is the open source counterpart to HackMD. Confused? Let us explain:

The public instance hackmd.io goes online.

HackMD is split into HackMD CE and HackMD EE.
The team behind HackMD continues the development in a private fork (HackMD EE) and sells it at hackmd.io.
The community starts to work on the open source version (HackMD CE), but changed the license to AGPLv3.
The HackMD EE team rewrites their private fork in TypeScript and sells it at hackmd.io.

The HackMD EE team proposes to replace the community-code of CodiMD with their rewrite of HackMD EE by switching to an open-core model. To use the core in their private fork, they want to re-license the new open source code under Apache 2.0.
The community wants to keep their code and the AGPLv3 license.
The HackMD team continues to develop HackMD EE.
The community creates a hard fork of CodiMD into their own GitHub organisation
The HackMD team continues to maintain the CodiMD repo in the hackmd organisation.
The community maintains the hard fork of CodiMD repo.

The community begins the search for a new name.

The community chooses "HedgeDoc" as the new name. Meanwhile they start a complete rewrite of CodiMD in TypeScript.

The community publishes HedgeDoc 1.7 with the new name and the new logo.

The community will release HedgeDoc 2.0.